Trivia

Marlon is the fourth Trainer whose sprite animation shows him with an irregular entrance, coming from the right side. The others are Aaron, Koga, and Janine.

Being at level 55, Marlon's Jellicent in Challenge mode is the highest leveled Pokémon to be owned by a Gym Leader during the initial battle with them, tied with Giovanni's Nidoking and Rhydon in Yellow.